RESUMEN
The effects of two nitrogen (N) concentrations combining with three phosphorus (P) concentrations on Isochrysis zhangjiangensis growth and formation of fatty acid (FA) were investigated in this study. Biomass concentration, mass fraction, and productivity of FA in I. zhangjiangensis were low in N-deprived media. Under both N and P sufficiency conditions, the intake of P and N was 40 times and 4.7 times of the normal algal growth condition, respectively, indicating I. zhangjiangensis had the potential for removing P and N from high concentrated N and P salinity wastewater. This study also showed that P deficiency in N sufficient medium increased the FA content, however, the difference between P limitation and P deprivation was not significant (P > 0.05). In N sufficient and P limitation medium, FA productivity was the highest, with a composition suitable for biofuel, so, this condition was the optimal condition for biodiesel production from I. zhangjiangensis.
Asunto(s)
Biocombustibles/análisis , Haptophyta/metabolismo , Nitrógeno/metabolismo , Fósforo/metabolismo , Biocombustibles/microbiología , Biomasa , Medios de Cultivo/química , Ácidos Grasos/análisis , Haptophyta/crecimiento & desarrollo , Aguas Residuales/microbiologíaRESUMEN
BACKGROUND/AIMS: Programmed death ligand1(PD-L1) plays a role in the development and progression of non-small cell lung cancer (NSCLC). This study aimed to identify miRNA(s) that are responsible for regulation of expression of PD-L1 in NSCLC, and to investigate the role of PD-L1 in regulation of the cell cycle in NSCLC. METHODS: We predicted the target miRNA of PD-L1, which was miR-140, using the online tools TargetScan and miBase. In NSCLC cells obtained from clinical specimens, in addition to A549 and NCI-H1650 cell cultures, western blots were used to detect the level of expression of proteins, while real-time PCR was used to determine the level of expression of PD-L1, miR-140, cyclin E, and ß-actin. Transfection with miR-140 mimics, miR-140 inhibitors, and PD-L1 siRNA were conducted using commercial kits. To determine whether miR-140 directly binds PD-L1, a luciferase reporter gene with wild type or mutated PD-L1 was used. Cell viability was measured with the MTT assay, and PI staining was used for cell cycle analysis. RESULTS: We found low expression of miR-140 and high expression of PD-L1 and cyclin E in NSCLC cells. Over-expression of miR-140 suppressed the expression of PD-L1 by directly binding its 3' UTR, and was also associated with decreased expression of cyclin E and inhibition of cellular proliferation in A549 and NCI-H1650 cells. Inhibition of PD-L1, in the absence of manipulations to miR-140, also decreased the expression of cyclin E. CONCLUSION: We conclude that miR-140 directly suppresses PD-L1 and inhibits the miR-140/PD-L1/cyclin E pathway in NSCLC.
Asunto(s)
Antígeno B7-H1/metabolismo , Carcinoma de Pulmón de Células no Pequeñas/patología , Neoplasias Pulmonares/patología , MicroARNs/metabolismo , Regiones no Traducidas 3' , Células A549 , Antagomirs/metabolismo , Antígeno B7-H1/antagonistas & inhibidores , Antígeno B7-H1/genética , Carcinoma de Pulmón de Células no Pequeñas/genética , Carcinoma de Pulmón de Células no Pequeñas/metabolismo , Línea Celular Tumoral , Proliferación Celular , Ciclina E/genética , Ciclina E/metabolismo , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , MicroARNs/antagonistas & inhibidores , MicroARNs/genética , Interferencia de ARN , ARN Interferente Pequeño/metabolismo , Puntos de Control de la Fase S del Ciclo CelularRESUMEN
Conversion of organic wastes to syngas is an attractive way to utilize wastes. The produced syngas can be further used to produce a variety of chemicals. In this study, a hollow-fiber membrane biofilm reactor with mix cultures was operated at 55 °C to convert syngas (H2/CO2) into acetate. A high concentration of acetate (42.4 g/L) was reached in batch experiment while a maximum acetate production rate of 10.5 g/L/day was achieved in the continuous-flow mode at hydraulic retention time (HRT) of 1 day. Acetate was the main product in both batch and continuous-flow experiments. n-Butyrate was the other byproduct in the reactor. Acetate accounted for more than 98.5 and 99.1% of total volatile fatty acids in batch and continuous modes, respectively. Illumina Miseq high-throughput sequencing results showed that microorganisms were highly purified and enriched in the reactor. The main genus was Thermoanaerobacterium (66% of relative abundance), which was usually considered as H2 producer in the literature, however, likely played a role as a H2 consumer in this study. This study provides a new method to generate the high producing rate and purity of acetate from syngas.
Asunto(s)
Ácido Acético/metabolismo , Dióxido de Carbono/metabolismo , Hidrógeno/metabolismo , Consorcios Microbianos/genética , Aguas del Alcantarillado/microbiología , Thermoanaerobacterium/genética , Técnicas de Cultivo Celular por Lotes , Biopelículas/crecimiento & desarrollo , Reactores Biológicos , Ácido Butírico/metabolismo , Fermentación , Secuenciación de Nucleótidos de Alto Rendimiento , Aguas del Alcantarillado/química , Thermoanaerobacterium/metabolismoRESUMEN
The solar X-ray and Extreme Ultraviolet Imager (X-EUVI), developed by the Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences (CIOMP), is the first space-based solar X-ray and Extreme ultraviolet (EUV) imager of China loaded on the Fengyun-3E (FY-3E) satellite supported by the China Meteorological Administration (CMA) for solar observation. Since started work on July 11, 2021, X-EUVI has obtained many solar images. The instrument employs an innovative dual-band design to monitor a much larger temperature range on the Sun, which covers 0.6-8.0 nm in the X-ray region with six channels and 19.5 nm in the EUV region. X-EUVI has a field of view of 42', an angular resolution of 2.5â³ per pixel in the EUV band and an angular resolution of 4.1â³ per pixel in the X-ray band. The instrument also includes an X-ray and EUV irradiance sensor (X-EUVS) with the same bands as its imaging optics, which measures the solar irradiance and regularly calibrates the solar images. The radiometric calibration of X-EUVS on the ground has been completed, with a calibration accuracy of 12%. X-EUVI is loaded on the FY-3E satellite and rotates relative to the Sun at a uniform rate. Flat-field calibration is conducted by utilizing successive rotation solar images. The agreement between preliminarily processed X-EUVI images and SDO/AIA and Hinode/XRT images indicates that X-EUVI and the data processing algorithm operate properly and that the data from X-EUVI can be applied to the space weather forecast system of CMA and scientific investigations on solar activity.
RESUMEN
BACKGROUND: This study will assess the effectiveness and safety of extracorporeal shock wave lithotripsy (ESWL) for patients with kidney stones (KS). METHODS: A comprehensive and systematic literature records search for studies will be conducted in MEDLINE, EMBASE, Cochrane Library, WANGFANG, VIP, Chinese Biomedical Literature Database, and China National Knowledge Infrastructure. All these databases will be searched from inception to the present without language limitation. Cochrane risk of bias tool will be used to assess the methodological quality for all included studies. Statistical analysis is performed using RevMan 5.3 software. RESULTS: This study will provide synthesis of current evidence of ESWL for patients with KS through assessing primary outcomes of overall stone-free rate, and secondary outcomes of mean stone size (mm), pain intensity, urinary biochemical variables, mean hospital stay (day), quality of life, and adverse events. CONCLUSION: This study will provide recommendations for the effectiveness and safety of ESWL for patients with KS, which may help to guide clinician. PROSPERO REGISTRATION NUMBER: PROSPERO CRD42019157243.
Asunto(s)
Tratamiento con Ondas de Choque Extracorpóreas/métodos , Cálculos Renales/terapia , Litotricia/métodos , Humanos , Metaanálisis como Asunto , Evaluación de Resultado en la Atención de Salud , Proyectos de Investigación , Revisiones Sistemáticas como Asunto , Resultado del TratamientoRESUMEN
BACKGROUND: This study will aim to assess the effectiveness and safety of electrical stimulation (ES) for the treatment of patients with benign prostatic hyperplasia (BPH). METHODS: PubMed, EMBASE, Web of science, Springer, Cochrane Library, PsycINFO, Allied and Complementary Medicine Database, CBM, and China National Knowledge Infrastructure will be retrieved from inception to the September 1, 2019. No language limitation will be applied to this study. Randomized controlled trials (RCTs) that assessed the effectiveness and safety of ES for the treatment of patients with BPH will be considered for inclusion. Literature selection, data collection, and risk of bias assessment will be conducted by 2 investigators independently. Statistical analysis will be carried out using RevMan 5.3 Software. RESULTS: This study will summarize high quality RCTs based on the present evidence of ES for the treatment of BPH in several aspects, including changes in urological symptoms, changes in prostate size, urodynamic parameters, quality of life, and number and severity of adverse events. CONCLUSION: The findings of this study will provide latest evidence to appraise whether ES is an effective and safety intervention for patients with BPH. PROSPERO REGISTRATION NUMBER: PROSPERO CRD42019157241.
Asunto(s)
Terapia por Estimulación Eléctrica/métodos , Hiperplasia Prostática/terapia , Humanos , Masculino , Metaanálisis como Asunto , Ensayos Clínicos Controlados Aleatorios como Asunto , Proyectos de Investigación , Revisiones Sistemáticas como Asunto , Resultado del TratamientoRESUMEN
BACKGROUND: Extracorporeal shockwave lithotripsy (ESWL) has gained worldwide popularity as one of the most commonly used minimally invasive management of urinary tract stones. The objective of this study was to evaluate the efficacy and safety of ESWL for patients with kidney stones (KS). MATERIALS AND METHODS: This protocol established in this study has been reported following the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols. Web of Science, PubMed, Embase, Cochrane Library, China Biomedical Literature Database (CBM), China Knowledge Network Database (CNKI), Chinese Scientific Journal Database (VIP), and Wan Fang Database were searched for case-control studies in ESWL treating patients with KS until July 1, 2020. We will use a combination of Medical Subject Heading and free-text terms with various synonyms to search based on the Eligibility criteria. Two investigators independently reviewed the included studies and extracted relevant data. The relative risk (RR) and 95% confidence intervals (CIs) were used as effect estimate. I test, substantial heterogeneity, sensitivity analysis, and publication bias assessment will be performed accordingly. Stata 14.0 and Review Manger 5.3 are used for a meta-analysis. RESULTS: The results will be published in a peer-reviewed journal. CONCLUSION: The results of this review will be widely disseminated through peer-reviewed publications and conference presentations. This evidence may also provide helpful evidence of the efficacy and safety of ESWL treating patients with KS. PROSPERO REGISTRATION NUMBER: CRD42019157243.
Asunto(s)
Tratamiento con Ondas de Choque Extracorpóreas , Cálculos Renales , Litotricia , Humanos , Tratamiento con Ondas de Choque Extracorpóreas/métodos , Cálculos Renales/terapia , Litotricia/métodos , Proyectos de Investigación , Metaanálisis como Asunto , Revisiones Sistemáticas como AsuntoRESUMEN
Background: This study aims at investigating the effect of the Weifufang, an effective prescription for the treatment of gastric cancer developed by the Traditional Chinese Medicine (TCM)/Combination of TCM and Western Medicine Department of the Hunan Cancer Hospital, on gastric cancer xenografts in nude mice and its effect on the PTEN gene; it also aims at exploring the possible tumor suppression mechanism. Methods: Nude mice with xenografts were treated with different concentrations of the Weifufang for 2 weeks, and changes in tumor volume were observed. The histopathology of the tumor was detected by hematoxylin and eosin staining; PTEN gene expression in tumor tissues was detected by immunohistochemistry (IHC) and western blot. Results: After 2 weeks of treatment, tumor inhibition rates in the 5-flourouracil (5-FU) group, and in the Weifufang low-, middle-, and high-dose groups were 30.67%, 19%, 49.52%, and 29.36%, respectively. The IOD of the PTEN gene was detected by IHC. The values in the water group, the 5-FU group, and the Weifufang low-, middle-, and high-dose groups were 0.013 ± 0.004, 0.085 ± 0.062, 0.041 ± 0.024, 0.128 ± 0.032, and 0.061 ± 0.052, respectively. Except for the 5-FU group, the differences between the gastric compound middle dose-group and the other groups were statistically significant (p < 0.05). Results of PTEN expression detection by western blot: The expression levels in the water group, 5-FU group, and the Weifufang low-, middle-, and high-dose groups were 0.2240 ± 0.0172, 0.4200 ± 0.0228, 0.2760 ± 0.0163, 0.3840 ± 0.0133, and 0.3040 ± 0.0211, respectively. Except for the 5-FU group, differences between the Weifufang middle-dose group and the other groups were statistically significant (p < 0.05). Conclusion: The Weifufang may inhibit the growth of gastric cancer xenografts by upregulating PTEN gene expression. The middle-dose group had the best effect.
Asunto(s)
Adenocarcinoma/tratamiento farmacológico , Medicamentos Herbarios Chinos/administración & dosificación , Fosfohidrolasa PTEN/biosíntesis , Neoplasias Gástricas/tratamiento farmacológico , Adenocarcinoma/enzimología , Adenocarcinoma/genética , Adenocarcinoma/patología , Animales , Western Blotting , Línea Celular Tumoral , Relación Dosis-Respuesta a Droga , Fluorouracilo/administración & dosificación , Humanos , Inmunohistoquímica , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Fosfohidrolasa PTEN/genética , Distribución Aleatoria , Neoplasias Gástricas/enzimología , Neoplasias Gástricas/genética , Neoplasias Gástricas/patología , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Regional specification of PM2.5 pollution characteristics is crucial for pollution control and policymaking. Spatiotemporal variations of six criteria air pollutants and influencing factors in China were studied using hourly concentrations of PM2.5, PM10, SO2, NO2, CO, and O3 from 2015 to 2016. China was categorized into eight regions: north-east, northern coastland, eastern coastland, southern coastland, Yellow River middle reaches, Yangtze River middle reaches, south-west, and north-west. The 29 exemplary cities in China were also researched. It was found that the PM2.5 concentration in the northern coastland (Beijing-Tianjin-Hebei-Shandong) was the highest (72.28⯵g.m-3) among the eight regions, particularly in the city of Baoding, Hebei, which had an annual average PM2.5 concentration of 98.53⯵g.m-3. Average PM2.5 concentrations in 2015 and 2016 of China were 50.16 µg.m-3 and 46.61⯵g.m-3, respectively. Compared with 2015, the PM2.5 concentration decreased by 8.41% in 2016, the decline of PM2.5 in summer was the largest, followed by autumn, spring and winter. The average mean PM2.5 concentrations of the 29 exemplary cities in 2015 and 2016 were 54.66 µg.m-3 and 48.37⯵g.m-3, respectively, exceeding the limit for grade 2 of the national standards (35⯵g.m-3). National air pollution distribution has exploded geographically with influence of regional economic factors. Gaseous pollutant as well as geographical and socio-economic conditions influenced PM2.5 emissions. Effects of these factors on PM2.5 emissions varied across regions and decreased continuously from the northern region to the south-west and eastern coastland regions. This paper clearly identifies the regional characteristics and distribution of PM2.5, focusing on the effects of gaseous pollutant, geography and socio-economic development. Secondary transformation and vehicle exhaust across regions should be further studied.
Asunto(s)
Contaminantes Atmosféricos/análisis , Contaminación del Aire/análisis , Monitoreo del Ambiente/métodos , Gases/análisis , Material Particulado/análisis , Emisiones de Vehículos/análisis , Beijing , China , Ciudades , Ríos/química , Estaciones del Año , Factores SocioeconómicosRESUMEN
OBJECTIVE: Intrathecal dexmedetomidine has been used in spinal anesthesia during cesarean sections. The purpose of this meta-analysis was to investigate the effect of intrathecal dexmedetomidine on the adverse reactions of spinal anesthesia during cesarean section. METHODS: We searched for relevant studies using PubMed, Web of Science, and the Cochrane library. After screening studies and extracting data, we performed a meta-analysis on the effect of intrathecal dexmedetomidine during cesarean section. RESULTS: A total of 278 patients from 4 studies were included in this meta-analysis. The incidence of shivering in the dexmedetomidine groups was significantly lower than that in the placebo groups during cesarean section (RR=0.40, 95% CI [0.25, 0.65], P=0.0002). Intrathecal dexmedetomidine had no effect on nausea and vomiting (RR=1.08, 95% CI [0.68, 1.71], P=0.74), bradycardia (RR=1.33, 95% CI [0.31, 5.76], P=0.70), and hypotension during cesarean section (RR=0.78, 95% CI [0.59, 1.03], P=0.08). CONCLUSION: Intrathecal dexmedetomidine can effectively reduce the occurrence of shivering during cesarean section, but it does not affect the occurrence of nausea and vomiting, bradycardia or hypotension.
Asunto(s)
Anestesia Obstétrica , Anestesia Raquidea , Cesárea , Dexmedetomidina/farmacología , Tiritona/efectos de los fármacos , Dexmedetomidina/administración & dosificación , Femenino , Humanos , Inyecciones Espinales , Embarazo , Ensayos Clínicos Controlados Aleatorios como AsuntoRESUMEN
In order to study the effects of acid rain on forest soil respiration, three plots were selected in the conifer/broad-leaved mixed forests in the Three Gorges Reservoir area of the Jinyun Mountain (Chongqing) from January 2016 to April 2017. Two groups of treatments were set up:a trenched treatment and an untrenched treatment. Each group was treated with four simulated acid rain gradients of pH 4.5 (control), 4.0, 3.25 and 2.5. The characteristics of total soil respiration and heterotrophic respiration under the four simulated acid rain treatments were measured. Soil temperature and moisture were measured during the respiration measurements, and soil samples were collected to study the effects of soil pH, the carbon-nitrogen ratio, and fine root biomass on soil respiration. The results indicated that the total soil respiration and heterotrophic respiration of trenched and untrenched plots showed a similar seasonal variation trend. The annual mean soil respiration rates of the CK, T4.0, T3.25, and T2.5 treatments were 1.89, 1.88, 1.75, and 1.74 µmol·(m2·s1)-1, respectively, and the annual mean soil respiration rates of the RCCK, RCT4.0, RCT3.25 and RCT2.5 treatments were 1.37, 1.32, 1.19, 1.08 µmol·(m2·s1)-1, respectively. There was no significant differences between the quarterly average of the total soil respiration and heterotrophic respiration before June 2016 (P>0.05). However, after October 2016, the difference was significant (P<0.01) with CK > pH 4.0 > pH 3.25 > pH 2.5. The cumulative soil CO2 emissions of the T4.0, T3.25, and T2.5 treatments in 2016 decreased by 3.89%, 9.64%, and 11.24% respectively, compared with the control, and the RCT4.0, RCT3.25, and RCT2.5 treatments decreased by 6.79%, 13.23%, and 25.56%, respectively. The simulated acid rain treatments reduced the ratio of heterotrophic respiration in the total soil respiration, and the degree of reduction increased with the pH of the simulated acid rain, indicating that the effect of acid rain on the inhibition of heterotrophic respiration exceeded that of autotrophic respiration. Although the simulated acid rain treatments increased the temperature sensitivity of soil respiration (Q10), it had no significant effect on soil temperature and humidity (P>0.05). The soil carbon-nitrogen ratio and fine root biomass were significantly greater in comparison to the control after October 2016. Soil respiration was significantly positively correlated with fine root biomass and significantly negatively correlated with the soil carbon-nitrogen ratio. Soil temperature and water contributed only slightly to soil respiration under the four simulated acid rain treatments. Fine root biomass and the soil carbon-nitrogen ratio were critical factors for variation of soil respiration under acid rain.
RESUMEN
The effects of pore sizes on the in-situ utilization of synthesis gas (syngas, H2 and CO) mixed culture fermentation (MCF) in the hollow-fiber membrane biofilm reactor (HfMBR) are not clear. Thus, the ultrafiltration (R1) and microfiltration (R2) HfMBRs were constructed. Syngas was totally consumed within the formed biofilm in R1; contrarily, it accumulated notably in R2. In the batch mode of R1 and R2, volatile fatty acids (VFAs) of acetate, butyrate and caproate were the main metabolites, but the production rate of total VFA in R1 (61.9â¯mmol-C/(L·d)) was higher than that of R2 (27.6â¯mmol-C/(L·d)). In the continuous mode, the R1 performance was much better than that of R2, and the biofilm in R2 was even washed out. Furthermore, Clostridium (30.0%) was the main genus in the enriched biofilm of R1, which converted syngas to VFAs. Thus, the ultrafiltration membrane shall be the suitable candidate for syngas MCF.
Asunto(s)
Biopelículas , Fermentación , Reactores Biológicos , Clostridium , UltrafiltraciónRESUMEN
There have been no reports of H2 and CO2 mixed-culture fermentation (MCF) at 25⯰C in a hollow-fiber membrane biofilm reactor (HfMBR). In this study, H2 and CO2 MCF were conducted in an HfMBR at 25⯰C producing metabolites including acetate, ethanol, butyrate, and caproate. Compared to pure culture fermentation (i.e., Clostridium carboxidivorans P7), the MCF in HfMBR at 25⯰C produced a higher concentration of caproate in this study (3.4â¯g/L in batch 1 and 5.7â¯g/L in batch 2). The dominant genera were Clostridium_sensu_stricto_12 and Prevotella_7. The caproate was more likely formed from the pathway of acetate and ethanol rather than via butyrate and ethanol. Since caproate is more valuable than acetate and low temperature fermentation consumes less energy, this process of H2 and CO2 MCF at 25⯰C is appropriate for industrial application.
Asunto(s)
Dióxido de Carbono , Fermentación , Biopelículas , Reactores Biológicos , Clostridium , HidrógenoRESUMEN
A novel strategy for constructing multiple joined genes of acidic partner-mediated antimicrobial peptide is described. This strategy allows the expression of antimicrobial peptide by Escherichia coli in a stable form and with high yield. Cecropin A (1-8)-melittin (1-10) (CAME) hybrid peptide was selected as a model of antimicrobial peptide. An acidic fragment from magainin intervening sequence was fused to the antimicrobial peptide as a partner to neutralize the lethal effects on the host cells. Multiple copies of the fusion peptide gene were tandemly linked and cloned into the expression vector pET21a. Multimers were expressed at high levels, reaching up to 36% of total cell proteins, and expression levels were proportional to the degree of multimerization. The fusion proteins were mainly expressed as inclusion bodies, probably owing to cysteine residues in the multimers. The target CAME peptide was obtained by cleaving the multimers with cyanogen bromide and purified by cation-exchange chromatography. Recombinant CAME peptide showed strong antimicrobial activities against both Gram-negative and -positive bacteria. These results might provide an efficient solution for high-level expression of various kinds of antimicrobial peptides that are toxic to the host.
Asunto(s)
Escherichia coli/genética , Escherichia coli/metabolismo , Regulación Bacteriana de la Expresión Génica , Péptidos/química , Péptidos Catiónicos Antimicrobianos/química , Cationes , Cromatografía por Intercambio Iónico/métodos , Clonación Molecular , Cisteína/química , Expresión Génica , Vectores Genéticos , Concentración de Iones de Hidrógeno , Plásmidos/metabolismo , Proteínas Recombinantes de Fusión/química , Proteínas Recombinantes/químicaRESUMEN
As PM2.5 affect human health, it is important to target tree planting in the role of reducing air pollution concentrations. PM2.5 capture capability of greening trees is associated with leaf morphology, while quantitative research is scanty. In this paper, the PM2.5 capture capability of 25 species in Beijing and Chongqing were examined by a chamber device. Groove proportion, leaf hair, stomatal density, and stomata size were selected as indexes of leaf morphology. Results showed that groove proportion and stomata size significantly relate to PM2.5 capture quantity, while no significantly positive correlations were found for leaf hairs and stomatal density. Broadleaf species are conducive to PM2.5 capture for their rich leaf morphology and have an edge over coniferous in PM2.5 capture per leaf area. However, coniferous had a larger PM2.5 capture capability per tree due to the advantage of a large leaf area. Significant difference existed between the species in Beijing and Chongqing due to the different leaf morphology. Urban greening trees are diverse and the structures are complicated. Complex ecological environment may lead to different morphology characteristics. Climate and pollution conditions should be considered when greening.
Asunto(s)
Material Particulado/análisis , Hojas de la Planta/química , Tracheophyta/química , Material Particulado/metabolismo , Hojas de la Planta/anatomía & histología , Hojas de la Planta/metabolismo , Tracheophyta/anatomía & histología , Tracheophyta/metabolismo , Árboles/química , Árboles/metabolismoRESUMEN
Evergreen broad-leaved forest (EBF), bamboo forest (BF) and mixed conifer and broadleaved forest (MF) were selected as objects of study on Jinyun Mountain from May to October 2012. The main contents were to analyze the rainfall process and nitrogen input of atmospheric rainfall, throughfall and stemflow. The results showed that: (1) During the research period, the total precipitation was 564. 88 mm, and throughfall of EBF, BF and MF were 74.0%, 85.0% and 71.6% of rainfall, respectively, and stemflow were EBF (1.9%), BF(10.3%) and MF (1.6%), respectively. The relationship between throughfall, stemflow and atmospheric rainfall could be described by a significant linear equation (P < 0.05), and both throughfall rate and stemflow rate had an obvious logarithmic function relationship with atmospheric rainfall (P < 0.05). (2) The concentration of NO3(-) and NH4(+) of throughfall and stemflow were higher than those of atmospheric rainfall, of which the three typical forests ranked as MF > EBF > BF. The total inorganic nitrogen input of throughfall and stemflow were EBF (14.93 kg x hm(-2)), BF (15.31 kg x hm(-2)) and MF (18.93 kg x hm(-2)), respectively. (3) There was a significant linear relationship between inorganic nitrogen input and throughfall, stemflow for three typical forest stands (P < 0.05).
Asunto(s)
Bosques , Nitrógeno/análisis , Lluvia , Atmósfera/química , China , ÁrbolesRESUMEN
Fogs and hazes broke out many times in winter and spring of 2012-2013 in Beijing, inducing severe pollution of respirable particulate matters (PM10). As a fine particle component in PM10, PM2.5 would cause more severe air pollution if the proportion of PM2.5 to PM10 is high. Based on this, 30 monitoring stations recording the concentration of PM2.5 and PM1.0 all over Beijing were selected, and the contamination characteristics of particulate matters were analyzed, which further served to determine the characteristics of temporal and spatial pollution variations of PM2.5 and PM10. The distribution of PM2.5 and PM10 mass concentration in winter and spring in Beijing were derived by the Original Kriging interpolation method, and it was depicted from the figure that the concentration of particulate matters gradually increased from the northern mountain area to the southern part of Beijing; in the central urban area, the particulate concentration of the western region was generally higher than that of the eastern region, with certain differences between urban and rural area within some local areas. Monthly variation curve of PM2.5 and PM10 mass concentration showed single peak-valley pattern: the maximum was in January and the minimum was in April; daily variation indicated a good correlation between PM2.5 and PM10, both of which were significantly influenced by meteorological conditions; diurnal variation curve showed a double peak-valley type. Meteorological factors such as daily average temperature (degrees C), relative humidity (%), wind speed (wind scale), precipitation (mm) were chosen and their individual relationships with concentrations of PM10 and PM2.5 were investigated using Spearman rank correlation analyses. It was demonstrated that the concentrations of PM10 and PM2.5 were positively correlated with temperature and relative humidity, respectively, and strongly negatively correlated with wind speed; wind speed and relative humidity were two key factors affecting the distributions of PM2.5 and PM10 concentration.
Asunto(s)
Contaminantes Atmosféricos/análisis , Monitoreo del Ambiente , Conceptos Meteorológicos , Material Particulado/análisis , Estaciones del Año , China , Ciudades , Análisis Espacio-Temporal , Tiempo (Meteorología) , VientoRESUMEN
Four typical types of green shrubs of Beijing (Euonymus japonicus, Buxus microphylla, Berberis thunbergii cv. atropurpurea, Taxus cuspidate cv. nana) were selected to study their capacities in adsorbing and arresting PM2.5 using both field observations and air chamber simulations. Concurrently, in order to analyze the pollution characteristics of Beijing in winter and spring, the PM2.5 concentrations of December 2012 to May 2013 were collected. Experimental results showed that: From the gas chamber experiments, the ability to adsorb and arrest PM2.5 was in the order of Berberis thunbergii cv. atropurpurea > Buxus microphylla > Taxus cuspidate cv. nana > Euonymus japonicus, mainly due to the differences in leaf characteristics; Outside measurement results showed that the ability to adsorb and arrest PM2.5 was ranked as Buxus microphylla > Berberis thunbergii cv. atropurpurea > Taxus cuspidate cv. nana > Euonymus japonicus. Chamber simulation and outdoor observation showed that Buxus microphylla and Berberis thunbergii cv. atropurpurea had strong ability to adsorb and arrest PM2.5; Meanwhile, the slight differences between the chamber simulation and outdoor observation results might be related to plant structure. Compared to tree species, the planting condition of shrub species was loose, and it greened quickly; By analyzing the Beijing PM2.5 concentration values in winter and spring, it was found that the PM2.5 concentration was particularly high in the winter of Beijing, and evergreen shrubs maintained the ability to adsorb and arrest PM2.5.